Inside the camp, captive humans worked and slept and went about their lives.

Many sun-loving humans would much rather sleep through the icy, snow-shoveling season and wake to a warm spring.

Both humans and many animals sleep about once a day.

Adult humans normally sleep in cycles of 90 to 110 minutes each.

It's a place where humans sleep and are fed.

If living humans eat and sleep there, we need to be invited inside.

Of course, the humans could have been sleeping in the cave's recesses.

Besides, while the humans slept, they could be surprised by some problem that would prevent them from calling him on the transmitter.

Vampires, Bonnie remembered, couldn't enter a place where humans lived and slept unless they were invited.

The Oversoul has power enough to put the humans to sleep.